This invention relates in general to powered hand tools and more particularly to hand tools powered by a rotating flexible shaft or cable. Even more particularly, the invention relates to apparatuses incorporating multiple powered hand tools that accomplish differing purposes, such that the user selectively activates a particular tool when it is desired to perform a specific work operation.
It is common to have situations where a plurality of different operations, such as cutting, grinding, polishing, deburring, drilling, etc., needs to be applied to a given workpiece or object, such as for example in the fields of jewelry, wood working, dentistry or the like. In many cases, the different operations are performed by a powered hand tool having interchangeable, axially rotated tool bits, such as a hand drill, a polisher, a grinding disc, a wire brush, etc. Portable electric drills, routers, grinders or the like are well known powered hand tools. For operations requiring fine motor skills, the weight of the drive motor becomes a problem. To counter this weight problem, smaller handheld motors have been developed, such as those sold under the Dremel brand, and it is also known to provide a flexible drive shaft or cable between the drive motor and a tool bit holder or handpiece, such that the heavy motor can be suspended or placed onto a support. In either event, it is still excessively time consuming to utilize a single drive motor where each tool bit must be removed and replaced by a different tool bit when a different operation is to be performed, especially when the same tool bits may have to be used multiple times when working on an object.
To address the problem of the work stoppage and lost time that occur when it is necessary to interchange tool bits, it is known to provide work stations with multiple motors, each motor having a dedicated flexible drive shaft, dedicated tool piece and dedicated or interchangeable tool bits. A foot pedal actuator is typically provided to switch power on and off such that only the motor driving the desired tool bit of the moment is operational. Such an apparatus is shown for example in U.S. Pat. No. 5,245,735 to Tanashian. With this set-up, an operator may switch from one tool bit to another simply by putting down the first handpiece, which precludes receipt actuation of the first motor, picking up the second handpiece, which allows activation of the second motor, and depressing the foot pedal to activate the second motor to initiate rotation of the flexible cable and second tool bit.
An apparatus of such type that requires multiple motors is more expensive than one utilizing a single motor, so improved apparatuses have been developed wherein a single drive motor is used to operate multiple tool bits. These apparatuses typically involve complicated gearing, valves, clutch mechanisms or electrical circuits such that only one of the tool bits is powered at a time. It is also known to provide multiple tools mounted onto a turret such that each of the tools can be aligned and connected to a motor of fixed position. Such apparatuses are not practical for handheld tools driven by flexible shafts, since rotation of the turret would necessarily entail movement of all the cables, leading to entanglement and other problems.
It is an object of this invention to address the problems set forth above by providing an apparatus having a single motor to selectively drive at a particular time any one of a plurality of axially rotated tool bits through rotation of each tool bit's dedicated flexible drive shaft or cable, wherein the flexible cables are mounted in fixed relation along a track or pathway and wherein the motor itself is translated along the track or pathway for alignment and engagement with the particular flexible cable and tool bit to be utilized. It is a further object to provide such an apparatus wherein the motor is also moved in a direction at an angle away from the plane containing the track, most preferably perpendicularly, to release from a first flexible cable and connect to a second flexible cable, the motor being translated along the track after release from the first flexible cable to be properly positioned for connection to the second flexible cable.